score1=int(input())
score2=int(input())
score3=int(input())
if score1>=90:
    point1=4.0
else:
    point1=(score1/90)*4.0
if score2>=90:
    point2=4.0
else:
    point2=(score2/90)*4.0
if score3>=90:
    point3=4.0
else:
    point3=(score3/90)*4.0
GPA=(point1*3+point2*4+point3*5)/(3+4+5)
print(f'GPA:{GPA:.1f}')